A direct-current power supply apparatus disclosed in Patent Literature 1 described below is configured to feed an electric current to a reactor by short-circuiting switch means only once during a power supply half cycle and suppress a harmonic current and improve a power factor. However, when the switch means is short-circuited only once during the power supply half cycle, it is necessary to increase an inductance value of the reactor to suppress harmonics. Further, heat generation in the reactor increases when the inductance value increases. This is because, after an input current is fed by the operation of the switch means, when the input current decreases to zero, not only the power factor is deteriorated but a harmonics amount of a high-order component increases to be larger than usual. Further, this is because, in the short-circuit performed only once, to prevent the input current from decreasing to zero, it is necessary to store large energy in the reactor.
In a conventional technology of Patent Literature 2 described below, by short-circuiting the switch means twice or more in the power supply half cycle, it is possible to reduce the inductance value of the reactor and reduce the heat generation. Further, when the inductance value decreases, because the external shape of the reactor also decreases, it is possible to reduce the reactor in size.